Apparatus and method for monitoring of cathode ray tube panel manufacturing to reduce CRT cost and improve performance and yield

Abstract

A monitoring apparatus and method for measuring light output gradient of a faceplate panel includes a top plate having a center detector and a plurality of corner detectors mounted along a major surface thereof. Lenses are optically coupled to a respective detector, and radiometers are electrically coupled to a respective detector. A bottom plate spaced apart from the top plate has a plurality of light outputs mounted along a major surface thereof and positioned to be opposite each detector. A light source is optically coupled to each light output through a splitter. A computer is electrically coupled to the light source for receiving feedback therefrom and for controlling the light source. The computer is also electrically coupled to each radiometer for recording data therefrom. During monitoring, a faceplate panel having a matrix applied thereto is accurately positioned between the top and bottom plates such that the center detector is located approximately above the center of the faceplate panel. Light is passed from the light sources through the faceplate panel to the detectors under control of the computer. The light output measurements at each detector are recorded by the computer and calculation is made of a light output gradient based upon a comparison of the light output at the center detector to the light output at the corner detector.

1. A monitoring apparatus for measuring light output gradient of a faceplate panel comprising:
 a top plate having a center and a plurality of corner detectors mounted along a major surface thereof, lenses each being optically coupled to a respective detector, and radiometers each being electrically coupled to a respective detector;  
 a bottom plate spaced apart from the top plate having a plurality of light output mounted along a major surface thereof and positioned to be opposite each detector;  
 a light source being optically coupled to each light output through a splitter; and  
 a computer being electrically coupled to the light source for receiving feedback therefrom and for controlling the light source and being electrically coupled to each radiometer for recording data therefrom and for calculating a light output gradient based upon a comparison of the light output at the center detector to the light output at the corner detector.  
 
   
   
     2. The monitoring apparatus as recited in  claim 1  further comprising a bar code reader being coupled to the computer. 
   
   
     3. A method of measuring light output gradient in a faceplate panel comprising:
 providing a top plate having light detectors positioned at a central location and at least one corner;  
 providing a bottom plate having light sources positioned at a center and at least one corner corresponding to the locations of the detectors in the top plate;  
 providing a computer for controlling the light source and for logging data from the detectors;  
 positioning a faceplate panel having a matrix applied thereto between the top and bottom plates such that the center detector is located approximately above the center of the faceplate panel;  
 passing light from the light sources through the faceplate panel to the detectors under control of the computer;  
 recording the light output measurements at each detector;  
 calculating a light output gradient based upon a comparison of the light output at the center detector to the light output at the corner detector.  
 
   
   
     4. The method of  claim 3  wherein the light output gradient is stored and compared to an acceptable threshold value. 
   
   
     5. The method of  claim 4  wherein the faceplate panel is rejected and the matrix is reprocessed if the light output gradient is greater than the acceptable threshold value. 
   
   
     6. The method of  claim 4  wherein the stored light output gradient which is below the acceptable threshold value is monitored for a series of faceplate panels and utilized to make corrective adjustments to a matrix application process. 
   
   
     7. The method of  claim 4  wherein the stored light output gradient which is below the acceptable threshold value is utilized for matching a particular faceplate panel to other components which form a cathode ray tube.